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To prevent condensation in the furnace and vent system, the
following precautions must be observed:
1. The return- -air temperature must be at least 60_F
(16_C)db except for brief periods of time during warm- -up
from setback at no lower than 55_F (13_C) db or during
initial start- -up from a standby condition.
2. Adjust the gas input rate per the installation instructions.
Low gas input rate causes low vent gas temperatures, caus-
ing condensation and corrosion in the furnace and/or vent-
ing system. Derating is permitted only for altitudes above
2000 ft. (610 M).
3. Adjust the air temperature rise to the midpoint of the rise
range or slightly above. Low air temperature rise can cause
low vent gas temperature and potential for condensation
problems.
4. Set the thermostat heat anticipator or cycle rate to reduce
short cycling.
Air for combustion must not be contaminated by halogen
compounds which include chlorides, fluorides, bromides, and
iodides. These compounds are found in many common home
products such as detergent, paint, glue, aerosol spray, bleach,
cleaning solvent, salt, and air freshener, and can cause corrosion
of furnaces and vents. Avoid using such products in the
combustion- -air supply. Furnace use during construction of the
building could cause the furnace to be exposed to halogen
compounds, causing premature failure of the furnace or venting
system due to corrosion.
Vent dampers on any appliance connected to the common vent
can cause condensation and corrosion in the venting system. Do
not use vent dampers on appliances common vented with this
furnace.
ADDITIONAL VENTING REQUIREMENTS
A 4" (101 mm) round vent elbow is supplied with the furnace. A
5- -inch (127 mm) or 6- - inch (152 mm) vent connector may be
required
for
some
model
4- -inch- -to- -5- -inch (101 - - 127 mm) or 4- -inch- -to- -6- -inch (101 - -
152 mm) sheet metal increaser fitting is required when 5- -inch
(127 mm) or 6- -inch (152 mm) vent connector is used. See Fig.
34 - - 46 Venting Orientation for approved vent configurations.
NOTE: Vent connector length for connector sizing starts at
furnace vent elbow. The 4- -inch vent elbow is shipped for upflow
configuration and may be rotated for other positions. Remove the
3 screws that secure vent elbow to furnace, rotate furnace vent
elbow to position desired, reinstall screws. The factory- -supplied
vent elbow does NOT count as part of the number of vent
connector elbows.
The vent connector can exit the furnace through one of 5
locations on the casing.
1. Attach the single wall vent connector to the furnace vent
elbow, and fasten the vent connector to the vent elbow
with at least two field- -supplied, corrosion- -resistant, sheet
metal screws located 180_ apart.
furnaces.
A
field- -supplied
NOTE: An accessory flue extension is available to extend from
the furnace elbow to outside the furnace casing. See Product Data
Sheet for accessory listing. If flue extension is used, fasten the
flue extension to the vent elbow with at least two field- -supplied,
corrosion- -resistant, sheet metal screws located 180_ apart. Fasten
the vent connector to the flue extension with at least two
field- -supplied, corrosion resistant sheet metal screws located
180_ apart.
2. Vent the furnace with the appropriate connector as shown
in Fig. 34 - - 46.
3. Determine the correct location of the knockout to be re-
moved.
4. Use a hammer and screwdriver to strike a sharp blow
between the tie points and work the slug back and forth
until the slug breaks free.
CAUTION
!
CUT HAZARD
Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care
and wear appropriate protective clothing, safety glasses and
gloves when handling parts and servicing furnaces.
CAUTION
!
BURN HAZARD
Failure to follow this caution may cause personal injury.
Hot vent pipe is within reach of small children when
installed in downflow position. See the following
instruction.
An accessory Vent Guard Kit is REQUIRED for downflow
applications where the vent exits through the lower portion of the
furnace casing. See Fig. 38 and Product Data Sheet for accessory
listing. Refer to the Vent Guard Kit Instructions for complete
details.
The horizontal portion of the venting system shall slope upwards
not less than 1/4- -in. per linear ft. (21 mm/M) from the furnace to
the vent and shall be rigidly supported every 5 ft. (2 M) or less
with metal hangers or straps to ensure there is no movement after
installation.
SIDEWALL VENTING
This furnace is not approved for direct sidewall horizontal
venting.
Per section 12.4.3 of the NFPA54/ANSI Z223.1- -2012, any listed
mechanical venter may be used, when approved by the authority
having jurisdiction.
Select the listed mechanical venter to match the Btuh input of the
furnace being vented. Follow all manufacturer's installation
requirements for venting and termination included with the listed
mechanical venter.
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